ESO comes to mind.
Beef up local exploration to make more interactive environmental objects.
I like being able to go in every building in ESO and check the drawers and find items, search barrels, pots, drawers, etc. I'd like to see all buildings in ffxiv be accessible with more object interaction, maybe at times even have locked doors and at some point find or get a key from a drop etc to open them, maybe find a random treasure chest once in a while.
I think FFXI has a better glamour system. you can save as many outfits as you want and change them whenever you want. No need for prisms, no need to have the item in your inventory, no need to re-glamour a slot because you got a gear upgrade. It's just a book with all your favorite outfits saved, and you can switch through them all at the press of a button anytime.
FFXIVs gear upgrades faster than milk expires, I finally get my glamour all set, then I get a piece upgrade... wasting more glamour prisms and forcing me to hold more stuff in my inventory. Plus I cant save my favorite sets. :(
I think this game would be better with more mini-games. Like capture the flag, and blitzball, but make them huge things that you can do as alternatives to pveing all the time.
More detailed character customization (thinking like ESO, I almost never met anyone who looked like me in that game) and more broadly just more interaction with the dev team.
On the ESO forums there are a couple mods who's job seems to be to respond to player inquiries and pass relavent info on. You can tag them like twitter (so like @ZOSGinaBruno was the one I knew of) and if it's a question they get you an answer or if it's a request they seem to bounce up the reasonable ones as I've seen quite a few particularly around job balancing become reality. I think having a middleman between us and the devs basically would be nice.